Inflammatory bowel disease (IBD) is a complex chronic inflammatory disorder, with the two more common forms being ulcerative colitis (UC) and Crohn's disease (CD). IBD is a multifactorial disease that results from a combination of predisposing genetic factors, environmental triggers, dysbiosis of the gastrointestinal microbiota and an inappropriate inflammatory response (Man et al., 2011, Nat Rev Gastroenterol Hepatol, March, 8(3):152-68).
Several studies on fecal and mucosa-associated bacterial communities have shown that the microbiota of patients with Crohn's disease (CD) differ from those of healthy controls, as well as those of patients with ulcerative colitis (UC). Although the reported changes are not always consistent, numbers of Escherichia coli are generally increased, whereas Firmicutes are scarcer in CD patients (Peterson et al., 2008, Cell Host Microbe, 3: 17-27; Frank et al., 2007, Proc. Natl. Acad. Sci., 104:13780-13785). Whether these changes are causative factors or consequences of inflammation, it remains controversial. To date, several pathogens have been proposed as causative agents. In particular, adherent-invasive E. coli (AIEC) has been reported to be more prevalent in CD patients than in controls in several countries (United Kingdom, France and the USA) (Darfeuille-Michaud et al., 2004, Gastroenterology, 127:412-421; Martinez-Medina et al., 2009, Inflamm Bowel Dis., 15:872-882). AIEC strains have been isolated from ileal lesions in ˜35% of CD patients compared to ˜5% of healthy subjects. One of the features of AIEC is their ability to adhere and invade epithelial cells. It is known from various models that the binding of adhesins expressed on the bacterial cell surface to defined glycosylated receptors on the host tissue surface is considered to be an initial and critical step in pathogenesis, then opening a new avenue for therapy such as blocking the interaction between type 1 pili and CEACAM6, a known host receptor for FimH (Barnich et al., 2007, J. Clin. Invest., 117:1566-1574; Carvalho et al., 2009, JEM, vol. 206, no. 10, 2179-2189). Therefore, inhibition of adhesion, and consequently intracellular replication of AIEC in epithelial cells, may prevent establishment of a sub-mucosal infection leading to mucosal inflammation and epithelial barrier disruption.
It has also been demonstrated recently that FimH antagonists are potentially effective in treating urinary tract infections (J. Med. Chem. 2010, 53, 8627-8641).